CT imaging features such as stellate scar, spoken-wheel-like enhancement, and segmental enhancement inversion were more common in RO and they may help in differentiating RO from ChRCC.

No abstract

Metanephric adenoma tends to be a solitary, poorly defined margin, isodense or hypodense mass arising from the renal medulla with enhancement less than the cortex and medulla during all phases.

Osteoblastoma is a rare bone tumor which is mostly found in the vertebral column and long bone. We describe a 59-year-old woman with osteoblastoma in the right fifth posterior segment of the rib, whose presenting symptoms were right back pain for two years and awakened at night. Chest computer tomography (CT) and thoracic spine magnetic resonance (MR) imaging findings included an expansile lesion of the right fifth rib and an ossified matrix. Surgical resection of the lesion confirmed a benign osteoblastoma. 12 months follow-up revealed disappearance of right back pain. Rib osteoblastoma in plain film has been described previously; however, to our knowledge this is the only case report emphasized in CT and MR imaging.

BACKGROUNDMixed epithelial and stromal tumors of the kidney (MESTKs) are a rare entity (about a hundred cases reported). They occur almost exclusively in postmenopausal women, with only seven cases reported in men. As this entity is very rare, little is known on its imaging features, especially magnetic resonance imaging (MRI) findings. In women, at MRI, the cystic component shows T1 hypointensity and T2 hyperintensity, while the solid component shows T1 hyperintensity and T2 hypointensity.CASE SUMMARYWe report the computed tomography (CT) and MRI findings of MESTK in a 19-year-old male adolescent. To our knowledge, this case report is the first report of MRI findings of MESTK in male adolescents. The patient was admitted to Subei People's Hospital (Jiangsu Province, China) in July 2017 after a renal mass on the left side was detected by ultrasound during a clinical examination. Blood tests were all normal. Non-enhanced CT showed a round, well-circumscribed complex mass, approximately 45 mm × 40 mm in size. MRI revealed a clear well-circumscribed mass with a mixed arrangement of solid and cystic components. On T2 weighted images, some hypointensities were found in the solid areas. After contrast enhancement, moderate or mild enhancement was found in the solid component, which increased with time. A radical left nephrectomy was performed. The pathology analysis revealed a mixed epithelial and stromal tumor. The patient had no imaging findings of recurrence or metastasis at 12 months following surgery.CONCLUSIONThe possibility of MESTK should be considered in male adolescents. MRI can provide useful information for the preoperative diagnosis.